1. Field of the Invention
The present invention generally relates to a film-covered terminal and more particularly to a film-covered terminal in which a foil or plate-like electrode terminal is sealed with sealing films.
2. Description of the Prior Art
Referring to FIG. 2(a) of the drawings, in the conventional film-covered terminal, the opposite surfaces of a foil or plate-like electrode terminal 11 are respectively covered with sealing films 13 and 13' each composed of polyester, or the like, through bonding layers 12 and 12' each composed of a thermoplastic resin material, such as polyethylene, or the like. In this case, an end portion of the electrode terminal 11 is extended outward from the sealing films 13 and 13' so that it can be soldered to an external circuit. In manufacturing such a film-covered terminal, the bonding layers 12 and 12' are laminated in advance on the respective surfaces of the sealing films 13 and 13', the electrode terminal 11 is sandwiched between the sealing films 13 and 13' with the respective bonding layers 12 and 12' disposed inside, and then the sealing films 13 and 13' are pressed against the electrode terminal 11 at about 120.degree. C. whereby the bonding layers 12 and 12' are melted so as to perform bonding seal between the electrode terminal 11 and each of the sealing films 13 and 13'.
As shown in FIG. 2(b), however, there have been disadvantages in the conventional film-covered terminal that the sealing films 13 and 13' are apt to be separated from the electrode terminal 11 together with the bonding layers 12 and 12' and moisture is apt to enter the boundary surfaces a and a' between the electrode terminal 11 and the respective bonding layers 12 and 12', or the like.
To improve the above-mentioned disadvantage, a film-covered terminal in which a hot-melting agent of proper adhesion is coated over the respective surfaces of the electrode terminal 11 and the bonding layers 12 and 12' at the boundary surfaces a and a' has been tried. Even in this case, however, there is a further disadvantage that if external force is exerted onto a portion of the terminal, the adhesion of the bonding layers 12 and 2' is deteriorated, so that moisture may occasionally enter gaps between the electrode terminal 11 and the bonding layers 12 and 12'.